The Effect of Isolated Obestatin Hormone from Plasma on some Biochemical Parameters in Normal and Diabetic Rats

The study included an attempt to isolate and purify obestatin from healthy human plasma using different biochemical techniques. Two proteinous peaks had been isolated by gel filtration chromatography (Sephadex G-50) from the precipitate produced by precipitation using cold acetone. It was found that the second peak (peak B) only had an obestatin. Two proteinous components had also been isolated by the same technique using Sephadex G-25 from the peak B. It was found that the second peak (peak D) had a high concentration of obestatin . Furthermore, the purity of the isolated obestatin (peak D) had been identified by the reversed phase high performance liquid chromatography and by SDS-polyacrylamide gel electrophoresis technique. The results obtained from the RP-HPLC showed that there was a good identity in retention time between the standard and the isolated obestatin (peak D). The approximate molecular weight of partially purified obestatin was (2573 ± 100 Da) and (2660 Da) using gel filtration chromatography by Sephadex G-25 and ( SDS-PAGE) technique respectively. The effect of the isolated obestatin (peak D) on some biochemical parameters in normal and alloxan induced diabetic male rats had been studied. After one week of treatment, the results showed that the obestatin at the dose (1 µmol / kg of body weight / d) caused a significant decrease in the levels of glucose, total lipids, total cholesterol, triglycerides, LDL-C, VLDL-C and MDA, in a addition to a significant increase in the levels of HDL-C in normal and alloxan induced diabetic rats and GSH in alloxan induced diabetic rats. It was concluded that the isolated obestatin from plasma had a an important role in metabolism of glucose and lipid profile in normal and alloxan induced diabetic rats.